Our free HTTP Header Tester & Auditor allows system administrators, DevOps engineers, and web security auditors to instantly analyze HTTP response headers. Evaluate 6 core security header directives—including Content-Security-Policy (CSP), Strict-Transport-Security (HSTS), X-Frame-Options, X-Content-Type-Options, Referrer-Policy, and Permissions-Policy. Detect dangerous information disclosure risks (like verbose `Server` software version tokens or `X-Powered-By` badges), calculate an automated letter Grade (A+ to F), and export text audit reports. Operating 100% client-side in secure local JavaScript, no server headers or domain data are ever uploaded to external servers.
Paste your web server's HTTP response headers into the editor or select a sample preset (Hardened Production or Vulnerable Server).
The auditor evaluates CSP, HSTS, X-Frame-Options, Referrer-Policy, and scans for version information leaks.
Check your letter Grade (A+ to F), review missing header warnings, and download http-header-audit.txt.
Evaluates 6 essential security directives required to protect web applications against XSS, Clickjacking, MIME sniffing, and MITM downgrades.
Scans headers for exposed software version tokens (like `Server: Apache/2.4.6` or `X-Powered-By: PHP/5.4`) that compromise server security.
All header parsing and security score calculations execute locally in your browser. No domain names or server headers are transmitted anywhere.
HTTP Response Headers are metadata directives transmitted from web servers to client browsers. Security headers instruct user agents to enforce defensive boundary policies against Cross-Site Scripting (XSS), Clickjacking, and Protocol Downgrades.
Key security headers include Content-Security-Policy (restricts executable script domains), Strict-Transport-Security (enforces HSTS encryption), X-Frame-Options (blocks clickjacking framing), and X-Content-Type-Options: nosniff (prevents MIME sniffing).
Server fingerprinting headers (Server, X-Powered-By, X-AspNet-Version) leak backend software versions, enabling malicious actors to cross-reference targeted CVE vulnerabilities against unpatched software stacks.